Building GSL as a Universal Binary

GSL

The GSL (Gnu Scientific Library) is a robust set of math routines, very useful for scientific computing.  The comet program uses the GSL to generate random numbers, and though we don’t absolutely require the GSL, it is better (more random) than using the standard rand() function.

If you want to link against the GSL and make code that runs on multiple architectures on OS X, you’ll need a universal binary of the library, like this precompiled universal binary of the GSL for OS X, including the ppc, ppc64, i386 and x86_64 architectures.

Building GSL as a Universal Binary

The script I used to build it is below, and is based on this post.  If you want to compile it yourself, download the latest version of the GSL (.tar.gz file) from here or one of the mirrors, then run the script below in the same directory. If you’re worried about the compiler optimizations affecting accuracy, remove the ‘-O3′ from COMPFLAGS.  The finished libraries are in the ‘libs’ directory and the headers are in ‘include’.  The script makes universal libraries of all of the ‘.a’ files (though I only use libgsl.a)

#!/usr/bin/env bash

# possible archs: i386 ppc x86_64 ppc64
# note: ppc64 doesn't work in Snow Leopard
ARCHITECTURES="i386 ppc x86_64"

# number of cpus to use during compile
COMPILETHREADS=2

COMPILER=gcc-4.2
#COMPILER=/Developer/usr/bin/llvm-g++-4.2

# configure flags
CONFFLAGS="--disable-shared"

# compiler flags
COMPFLAGS="-O3"

# find the name of the source file
SOURCEFILE=`find . -name "gsl*.tar.gz" -depth 1`
SOURCEFILE=${SOURCEFILE:2:100}
GSLVER=${SOURCEFILE%.tar.gz}

# unzip the main source file
tar -xzf $SOURCEFILE

for ARCH in $ARCHITECTURES
do
echo Compiling for ${ARCH}...

# copy source to new directory
cp -r ${GSLVER} ${GSLVER}_$ARCH
cd ${GSLVER}_$ARCH

# configure for architecture
if [ "$ARCH" != "ppc64" ] ; then  # not sure why we have to do cross compile for ppc64 but not ppc...
env CC="$COMPILER" CFLAGS="-arch $ARCH $COMPFLAGS" LDFLAGS="-arch $ARCH" ./configure $CONFFLAGS --build=$ARCH
else
env CC="$COMPILER" CFLAGS="-arch $ARCH $COMPFLAGS" LDFLAGS="-arch $ARCH" ./configure $CONFFLAGS --host=$ARCH
fi

# compile for architecture
make clean ; nice make -j $COMPILETHREADS

cd ..

done

mkdir include
mkdir libs
cp `find ${GSLVER} -name "*.h"` include

echo
echo
echo Making Universal Binaries...

find ${GSLVER}_$ARCH -name "*.a"

for LIBRARY in `find ${GSLVER}_$ARCH -name "*.a"`
do
echo
LIB=`basename $LIBRARY`
echo Library: $LIB
find . -name $LIB
lipo -create `find . -name $LIB | xargs` -output libs/$LIB
lipo -info libs/$LIB
done

echo
echo Universal Binaries:
echo
lipo -info libs/*.a

Related posts:

1. Installing VTK on Mac OS X Download Universal Binaries of the VTK libraries for OS X here (also how to build them yourself). The comet program...